213665-59-9Relevant academic research and scientific papers
Reversible anion binding in aqueous solution at a cationic heptacoordinate lanthanide centre: Selective bicarbonate sensing by time-delayed luminescence
Dickins, Rachel S.,Gunnlaugsson, Thorfinnur,Parker, David,Peacock, Robert D.
, p. 1643 - 1644 (1998)
Reversible displacement of up to two metal bound water molecules at a coordinately unsaturated, cationic lanthanide centre is signalled by increases in the luminescence intensity or lifetime of the emissive lanthanide: selective chelation of hydrogencarbo
Structural and NMR investigations of the ternary adducts of twenty α-amino acids and selected dipeptides with a chiral, diaqua-ytterbium complex
Dickins, Rachel S.,Batsanov, Andrei S.,Howard, Judith A.K.,Parker, David,Puschmann, Horst,Salamano, Stefania
, p. 70 - 80 (2004)
A detailed investigation of the nature of the binding of each of the 20 common α-amino acids and various selected dipeptides to a chiral, diaqua-ytterbium complex in aqueous solution has been carried out. Analysis of the dipolar 1 NMR paramagnetic shifts suggests that the α-amino acids form a common chelated structure within a nine-coordinate mono-capped square antiprismatic coordination environment, with the amine N axially disposed. Crystal structures of nine chelated YbL1-amino acid adducts (Gly, Ala, Ser, Thr, Met) confirm this. The ternary complexes with dipeptides (e.g. Gly-Ala, Gly-Ser, Gly-Met, Gly-Asp, Gly-Asn, Gly-His, Ser-Met, Asp-Phe, His-Gly) also favour the terminal amine as the axial donor with the proximate amide group binding to generate a five-ring chelate. Evidence for chelation through side-chain functionality was found only in the case of N-terminal Asp. The chiral environment about the ytterbium ion upon amino acid binding has also been probed using near-IR circular dichroism spectroscopy.
SYNTHESIS OF TRIS N-ALKYLATED 1,4,7,10-TETRAAZACYCLODODECANES
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Page 9-10, (2008/06/13)
A directly synthetic method for preparing tris-alkylated 1,4,7,10-tetraazacyclododecanes by the reactions of 1,4,7,10-tetraazacyclododecane (cyclen) and appropriate electrophiles is accomplished in high yield. The method provides operational convenience,
